Justin Timberlake and Jessica Biel have ''always wanted'' another child.

The couple - who already have two-year-old son Silas Randall - are reportedly keen to add to their family and are hoping for a little girl.

A source told RadarOnline.com: ''It's 'when' not 'if' they'll be adding to their family. They've always wanted another kid, but they waited until things got better. Now they are trying, hoping for a girl.''

Meanwhile, Justin previously revealed he wants to have ''as many kids'' as he can and sooner rather than later.

He shared: ''I want to have as many kids as we can, if I'm being honest. I've never felt more inept my life. You wake up and all of a sudden there's this human being you're responsible for.''

And the 37-year-old singer had previously admitted he would love to have a daughter with Jessica.

Speaking at the Hollywood Reporter's Power 100 Women in Entertainment breakfast, he said: ''I feel really inspired to be in this room. People like Angelina [Jolie], Sherry [Lansing], Shonda [Rhimes], Nancy [Dubuc] and you strong women that are younger than me ... Oh my God, I've got to have a daughter. I'm ruined after today. To the men in this room ... I think we actually are here because we deserve the opportunity to speak up, to say when something is not right. We need to get on board. It's not a responsibility, it's our privilege. It's our privilege because at the end of the day if you can be lucky enough to be raised by a strong woman and convince a strong woman [Jessica Biel] to marry you, you will realise that we are nothing without the strength of women.''